As well known in the art, particularly in the field of fuel dispensing, EPA, in addition to various state regulatory agencies, such as the California Air Resources Board, have placed stringent demands upon the oil companies, in addition to the supplier of equipment for use in dispensing fuel, to totally eliminate the escape of any vapors or fumes into the atmosphere. This pressure has been placed upon the oil companies, and which is imposed upon the supplier of equipment, such as the companies furnishing dispensers, the companies providing underground storage tanks, and even those companies that furnish fuel dispensing nozzles. All of the efforts are directed towards capturing the vapors, and returning them back to the underground storage tank. Of more recent origin, is the on board vapor recovery, where the vapors are collected in the fuel tank, passed through a carbon filter, which eventually condenses some of the vapors, and then those condensed fumes are delivered to the carburetor or fuel injectors, for burning.
Obviously, it is impossible to obtain one hundred percent efficiency in capturing all vapors, and preventing some of their emission into the atmosphere. Normally, in the past, CARB required that at least ninety-five percent of the vapors be captured. This realistically recognized that about five percent of the fumes were going to escape, regardless what stringent efforts were placed upon the equipment to capture such fumes, and prevent their escape to the ambient air.
Recognizing that an extremely high efficiency in vapor collection is a requirement that is here to stay, efforts are now being made to refine the vapor collection techniques, and as identified in this current invention, to further attempt to process the vapors, in order to provide for their better handling, more efficient storage, and to minimize vapor escape into the atmosphere, in an effort to add further efficiency to this concept to attain vapor reduction, with respect to their escape into the ambient atmosphere.
Examples of vapor collecting techniques, through the use of coaxial hoses, etc., pumps within the dispenser, that return the vapors back to the underground storage tank, are well known in the art. For example, U.S. Pat. No. 5,285,744, shows a coaxial hose assembly, where returning fuel vapors from the nozzle are directed to the pump, through a coaxial hose. U.S. Pat. No. 5,197,523, shows a dispensing nozzle improvement for extracting fuel from the vapor return line, for a fuel dispensing system, which in this particular instance, the vapors are pumped back to the underground storage tank. The vapor control valve of U.S. Pat. No. 5,394,909, shows a method for capturing vapors, and returning them via the nozzle back to underground storage. U.S. Pat. No. 5,476,125, discloses a vapor recovery gasoline dispensing nozzle, for collecting vapors, and returning the same to the source of the fuel, its underground storage fuel tank. U.S. Pat. No. 5,520,228, discloses another fuel extraction coupling means for a nozzle, in order to keep the vapor return line clear, so that the vapors may be returned and pumped back through the dispenser to the underground storage. U.S. Pat. No. 4,566,504, shows an insertion tube liquid evacuator system for vapor recovery hose. Finally, U.S. Pat. No. 4,687,033, shows a venturi liquid evacuator system for maintaining clear vapor path in vapor recovery hoses. All of these various embodiments, as previously patented, many of them to the Assignee of this current invention, show the history of structures and methods for collecting vapors, and attempting to return them to the underground storage tank, with some degree of efficiency.
Other means are provided for attempting to handle the vapors being returned to the underground storage tank, in order to prevent their escape. Such other means, on the other hand, for accomplishing this result as in use are generally very complicated, and costly to install and maintain. Such systems have a tendency to reduce the system pressure by removing vapors, and processing them to remove or destroy the harmful hydrocarbons. This is a costly procedure. Furthermore, its effectiveness, is not overly efficient, unless the system is designed and installed to attain perfection, and that can be quite costly to operate, and must be carefully supervised. For example, others have attempted to produce a type of vapor processor, that seek to remove or minimize the hydrocarbons from within the returning vapors, but none of these vapor processors include the use of any type of cooling or chilling of the vapors, to attain beneficial results. For example, at the large tank farms, where fuel arrives by pipeline, large refrigeration units have been used to condense the hydrocarbon vapors back into liquid, to prevent their escape into the atmosphere. But, refrigeration units used in this manner are designed for condensation purposes, and not for temperature reduction per se.